Engine Crankcase Breather Kit Porsche 957 Cayenne S / GTS 4.8L 2009-2010

Engine Crankcase Breather Hose Kit

The engine crankcase breather hose is a key part of your vehicle’s positive crankcase ventilation (PCV) system. Its main role is to route pressurized gases from the engine crankcase to the PCV valve (also called the air/oil separator). The PCV valve captures harmful oil  vapers , drains them back into the engine, and redirects the cleaned air to the intake system to be burned during normal combustion.

Without a properly functioning breather hose, your engine can develop performance issues, oil leaks, and even emissions failures.

Why the Engine Crankcase Breather Hose Matters

During combustion, engines naturally produce positive crankcase pressure. This pressure combines with heat and oil vapers inside the crankcase. The breather hose is designed to handle this flow and keep your PCV system working efficiently.

Over time, however, exposure to heat, oil, and pressure makes the breather hose a common failure point. When damaged, it can cause poor performance, check engine lights, and increased emissions.

Common Symptoms of a Failing Crankcase Breather Hose

• Cracks, leaks, or breaks – Heat and oil vapers degrade rubber or plastic over time, leading to air leaks.
• Broken connectors or clips – Brittle plastic can snap during service or due to age.
• Visible damage – Hoses may split, soften, or harden, creating noticeable holes.
• Check Engine Light (CEL) – Unmetered air from a leak often triggers intake-related fault codes.
• Engine misfires or rough idle – Severe air leaks upset the air/fuel mixture, causing misfires.

Oil residue or odour – Escaping vapers leave oily deposits on the hose, engine block, and nearby components. In severe cases, you may smell burning oil.

Why You Shouldn’t Ignore a Bad Breather Hose

A faulty crankcase breather hose affects engine performance, fuel efficiency, and emissions compliance. Left untreated, it can cause long-term engine damage and costly repairs.

If you notice any of the above signs, it’s important to inspect and replace your crankcase breather hose as part of regular PCV system maintenance.

Diagram ref no 13 (Cyl 1-4) or 14 (Cyl 5-8)

NOTE: This part is compatible only with 957 Cayenne S/GTS models produced from the 2009 model year onwards. It is not compatible with earlier models equipped with the silver AOS.